I'm asking this question because I would like to have an educated response for those ninnies who drink "ice beers" and think that its the greatest. Is it just a lager fermented at extra low temps or is there a little more too it?

True "ice beer" was a German style (I can't find the spelling of the word) that chilled bock beer down below freezing than removed the ice to obtain a smooth highly alcoholic beer. But it was Bock and not 'light' lager.

A process was patented in the US to get the smooth consistancy of the German "Icebock" but not the increase in alcohol. This is considered, by our friends at the BATF, as distilation which is illegal without a licence. Some micros have started to distill a house Gin or Rum. They may be relaxing some of the regs to collect more taxes. Miller GMD is one brand that the entire brewing proceedure is build around the ceramic cold filter.

The real bottom line to the majors is that they (at a substantial cost) take a large volume of 'green' beer process it quickly, to try and get a 'paletable' flavor. When you can shave 28 days off Hectoliters or thousands of barrels of beer, package and ship you are cutting cost and adding profit. From the technical perspective, completely American, it is novel but I think the products taste like #$@%. Beer, though technically "perfect" is of very low quality as judged by accepted brewing standards. Marketing all marketing.

When you run into this discussion, best it by pointing to the fact that if this process wasn't so good the beer produced would have been poured down the drain. I will look further if you are interested. Let me know.

I tried filtering several years ago as a way to speed up clarification (and drinking)of ales. I used both a 3 and 5 micron mesh. The 3 micron left me with a wee-wee colored, flavorless, bodiless, watery beer-like substance. The 5 micron left the beer somewhat intact but didn't remove all the cloudiness so I pitched the whole set-up. My question is: how on earth does Miller end up with anything even remotely resembling beer after passing it through a filter fine enough (I assuming <3 micron) to negate the need for pateurization?

1) The original ice beer as pointed out in Tom's post was German and is called Eisbock. This lager is a Kulmbach specialty traditionally brewed by freezing a Bock or Doppelbock and removing the water ice to concentrate the
flavor and alcohol content. The process of concentrating the alcohol content by freezing may impart significant smoothness to the flavor.

The effective OG range due to the freezing effect is 1.092-1.150. Here are the specifications for the style:

Appearance: Deep gold to dark brown in color. Lagering should provide good clarity. Head retention may be impaired by higher than average alcohol content.

Flavor: Rich malt and concentrated alcohol. No hop flavor. Hop bitterness just balances the malt sweetness to avoid a cloying character. No diacetyl or esters.

Mouthfeel: Full-bodied. Carbonation low.

Typical Ingredients: Pale lager malt for pale versions, Munich and Vienna malts for darker ones and occasionally a small fraction of dark roasted malt in those.

Continental European hops for bitterness only.

Lager yeast.

Water hardness will vary.

OG: 1.064-1.120 TG: 1.023-1.035
IBUs: 25-50
SRM: 18-50
ABV: 8.6-14.4%

North American Example: Niagara Eisbock.

2) What we now call "Ice Beer" was first produced in Canada by Molson. Molson Ice is among the few brands that remain on the market in the US.

3) The process also includes centrifugation, otherwise, the ceramic filter would bind. The ceramic filtration technology is used extensively in the macro brew industry for regular filtration. The ceramic filtration components and process was a Japanese invention that was co-developed by Asahi and Kyocera (yes... the cell phone manufacturer, which is a huge technology conglomerate). They developed it for use to produce all of their beer styles. The Canadians were first to use it in conjunction with ice centrifugation.

4) Ice separation and filtration is not classified by the BATF as equal to steam column distillation and it is legal for home brewers to make this beer. Licensed commercial brewers are allowed to produce this style without a spirits production license as long as they comply with state alcohol % maximums for malt based beverages. This ruling has been based on the proof of the beverage produced, not the method of production.

What was the style of filter you used ? Cartridge designed for under-sink water filtration maybe ? If so, I have used 5,3 and 1 micron cartridges with no stripping. This is because the ratings are NOMINAL not exacly what they are rated for. The effective filtration of a 1 micron cartridge is in the 1.9 to 2.4 area, a 3 is in the 3.5 to 4.2 area and a 5 goes as high as 6.5 ! The results you describe if using these types of filters lead me to suspect that you used carbon or media containing filters. Both of these filters will strip most of the color and flavor out of a beer and is similar to how Zima is produced.

A bit on filtration:

Yeast averages 10 microns, so any filter rated as 7 micron nominal or below will completely remove all of the yeast if there is no blow-through and the proper pressure differential between filtering vessels is observed.

Soluble and insoluble proteins can be as small as 6 microns and are well filtered by 5 micron nominal cartridges and below if properly used.

Bacteria can go as small as 1 ~.3 microns and lower, so they are difficult to filter without stripping the beer, but the 1 micron filter can
help reduce the most common beer spoilers when used properly.

The keys to proper filtration are:

1) Removal of the bulk yeast load by transfer to the secondary and/or tertiary fermenter prior to filtration. Otherwise, higher pressures are needed to filter the beer and there is the possibility of binding.

2) 24 hours prior to filtration, cool the beer as low as possible.... below 32 deg. F. is best. This will allow the proteins that are in solution to fall out of solution and become visible as chill haze. If you can see it... it will be filtered out.

3) Filter BEFORE the beer is carbonated ! Otherwise, the CO2 released by the filtering process will spread the pores out in the filter and destroy your efforts.

4) Filter under counter pressure with CO2. There are a number of reasons for this: 1) Reduced oxygen pickup, 2)No loss due to foaming and the biggest: 3) The best clarification that the filter used will offer with a greatly reduced chance of binding. I can explain how to pull this off properly if anyone is interested.

5) DON'T GET IN A HURRY ! The most pressure you should filter with on the pre-filter side is 12~15 PSI and this would only be toward the end of the run. Initially, I start with 5 PSI and slowly increase it to maintain the post filter PSI exiting into the keg. If you start to hurry, there are only two possible outcomes: 1) Bound filter or 2) Underfiltered beer.

And a correction regarding the Miller question:

Actually, Miller is cold filtered and pasturized. The bottled product is processed through a tunnel pasturizer and the kegged product is pasturized in-line on the way to the kegs which are steam sterilized prior to filling.

I thought the whole point of "genuine draft" is that it is not heat pasteurized.

Back to home filtering. I used purpose-designed fiber filter pads. The beer had settled in 20 degree weather for 4-5 days prior to filtering with CO2 pressure (probably higher than you recomended toward the end) and the 5 micron still left chill haze and the 3 definitely stripped all of the character out of my hard earned brew.

The maketing mantra "cold filtered" is exactly what it sounds like... filtering cold, which, as explained prior, brings formerly invisible proteins out of solution so they can either settle or be filtered.

Now that I am aware that you use fiber pads I can make some more valid obervations.

The type of filter pads I am aware of that are available to homebrewers are designed for wine. Wine is seldom filtered when young and usually has had a lot of settling time (1.5 + months). Therfore, most of the particulates have settled out of the must. The job of the filter is then to simply "polish" the wine, not remove a high particulate load like that of recently fermented beer. These filters are also a lot closer to the actual micron rating printed on their wrapper than the nominal rating displayed for cartridge filters. They are perfectly suited for filtering beer IF the yeast/protein load is not very high. The reason they have a problem when the yeast/protein load is high is twofold: 1) The surface area through with the beer actually passes is not very large and 2)their flow rate is low in comparison to cartridge filters. Therefore, as they bind up with particulates, they produce a tighter and tighter filtration. This is most likely the cause of the stripping you described with the 1&3 micron pads. With the 5 micron pads, the reduced throughput toward the end of the run might have made you want to "crank" the pressure up to speed the filtration. If so, this may have caused pad blow through or channel breach and re-established the haze in the finished beer.

I see no reason for you to change the method of filtration as it produces great results when used properly. Here are my recommendations:

1) Chill the beer to 32 deg. f. or below and let rest for at least 24 hours. Adding an isinglas solution prior to the chill down will help to settle the yeast load. Rack off the beer leaving as much of the particulate load behind as possible.

2) Never filter beer without counterpressure ! Filter from a sealed pressure vessel through the filter and exiting into another sealed pressure vessel (Cornelius Cylinder to filter housing to Corneilius Cylinder is the most common setup).

3) Set the pressure regulator on the gas outlet of the receiving cylinder 3~5 PSI lower than the CO2 regulator pressure set on the pre-filtered beer's cylinder. If the beer flow rate slows unacceptibly, adjust the regulator upward, but make sure to reset the receiving cylinder's relief valve to maintain the original pressure differential. This will keep the pads from tightening to the point of stripping or outright binding.

4) If your filter housing uses 4 pads or less, use two passes: filter the beer first using 5 micron pads, then follow with the 3 micron pads. This should leave you beer very bright and unstripped.

5) If you happen to be blessed with a filtration housing that holds more that 4 pads, you could try installing 3-5 micron pads followed by 2 or more 3 micron pads. I do something similar to this at my brewery, just many more pads. If the proper flow rates are observed and the outlet pressure is balanced within 3~5 PSI of the inlet pressure, this method will produce very bright beer.

When I said I pitched the whole set-up I meant just that-I threw it away. This was done in a fit of pique and rather childish I now realize, but changing 15 gallons of highly hopped IPA into 15 gallons of Bud Light pissed me off.
You mentioned something before about using spun or string wrapped cartridges. Does this work? They are definitely cheaper and their housings are more ammenable to plumbing than the stamped sheet metal thing I had before.
This is off the point but you sound like you would know. I have a friend who owns a sports bar. He has asked several times about me supplying him with a couple of kegs per month of my standard ale. He wants to make it sort of a house signature beer. What kinds of tax and ATF headaches are involved in doing this legally? I know this is not a simple question. If you could just give me a paragraph on whether this is worth research further I would greatly appreciate it. Matt

[quote="Mesa Maltworks"]What was the style of filter you used ? Cartridge designed for under-sink water filtration maybe ? If so, I have used 5,3 and 1 micron cartridges with no stripping. This is because the ratings are NOMINAL not exacly what they are rated for. The effective filtration of a 1 micron cartridge is in the 1.9 to 2.4 area, a 3 is in the 3.5 to 4.2 area and a 5 goes as high as 6.5 ! The results you describe if using these types of filters lead me to suspect that you used carbon or media containing filters. Both of these filters will strip most of the color and flavor out of a beer and is similar to how Zima is produced.

A bit on filtration:

Yeast averages 10 microns, so any filter rated as 7 micron nominal or below will completely remove all of the yeast if there is no blow-through and the proper pressure differential between filtering vessels is observed.

Soluble and insoluble proteins can be as small as 6 microns and are well filtered by 5 micron nominal cartridges and below if properly used.

Bacteria can go as small as 1 ~.3 microns and lower, so they are difficult to filter without stripping the beer, but the 1 micron filter can
help reduce the most common beer spoilers when used properly.

The keys to proper filtration are:

1) Removal of the bulk yeast load by transfer to the secondary and/or tertiary fermenter prior to filtration. Otherwise, higher pressures are needed to filter the beer and there is the possibility of binding.

2) 24 hours prior to filtration, cool the beer as low as possible.... below 32 deg. F. is best. This will allow the proteins that are in solution to fall out of solution and become visible as chill haze. If you can see it... it will be filtered out.

3) Filter BEFORE the beer is carbonated ! Otherwise, the CO2 released by the filtering process will spread the pores out in the filter and destroy your efforts.

4) Filter under counter pressure with CO2. There are a number of reasons for this: 1) Reduced oxygen pickup, 2)No loss due to foaming and the biggest: 3) The best clarification that the filter used will offer with a greatly reduced chance of binding. I can explain how to pull this off properly if anyone is interested.

5) DON'T GET IN A HURRY ! The most pressure you should filter with on the pre-filter side is 12~15 PSI and this would only be toward the end of the run. Initially, I start with 5 PSI and slowly increase it to maintain the post filter PSI exiting into the keg. If you start to hurry, there are only two possible outcomes: 1) Bound filter or 2) Underfiltered beer.

And a correction regarding the Miller question:

Actually, Miller is cold filtered and pasturized. The bottled product is processed through a tunnel pasturizer and the kegged product is pasturized in-line on the way to the kegs which are steam sterilized prior to filling.